Lever device for operating a hydraulic actuator, particularly for motorcycles

ABSTRACT

A lever device for operating a hydraulic actuator for a motorcycle, comprises a support that can be connected to a bearing structure, a hydraulic actuator connected to the support, a main lever, pivotally connected to the support and intended to be operated by being moved close to or away from said hydraulic actuator, a control rod and an adjustment member that are interposed in series between the main lever and a piston of the hydraulic actuator such as to transmit an operating movement from the lever to said piston. The adjustment member pivots about an axis of adjustment and defines a seat that accommodates an end of the control rod. The seat is eccentric to the axis of adjustment, whereby rotation of the adjustment member changes the orientation of the control rod relative to the axis of rotation of the lever, and thus the lever ratio.

The present invention relates to control lever devices for vehicles,particularly to a lever device for motorcycles in which the lever ratiocan be adjusted.

In motorcycles, the brake and clutch are manually actuated by means of alever device that is mounted on the handlebar of the motorcycle, ahydraulic pipe extending from this lever device to the system to becontrolled, such as a brake or a clutch.

The lever of the lever device is usually arranged along the grip of thehandlebar and the motorcyclist, in order to actuate the lever, grips thehandlebar together with the lever and clenches the hand such as torotate the lever towards the grip. The movement of the lever produces athrust force acting on a hydraulic piston, the stroke or positionthereof defining the fluid pressure inside said hydraulic pipe for thecontrol of the brake or clutch.

The lever ratio of a lever device for brake or friction is generallydefined as the ratio between the manual force application arm and theapplication arm of the hydraulic fluid resisting force, i.e. thehydraulic piston, relative to the lever fulcrum. This lever ratio isusually set invariable, and in order to arrange different lever ratiosfor various requirements (e.g. road cycling vs. downhill mountain bikingor road motorcycling vs. motocross, track or rain, etc.) themanufacturers of braking systems offer various basic models havingdifferent distances between the hydraulic piston and the fulcrum of thebrake lever. It is understood that this solution cannot meet therequirements of those who desire to change the lever ratio of the brakewithout having to replace the entire lever operating device.

In order to meet said requirement for adjusting the lever ratio,solutions have been proposed which provide for the adjustment of thefulcrum position relative to the hydraulic piston or the adjustment ofthe lever length. These are mechanically complex solutions and result inan inevitable increase in the overall dimensions of the lever device ascompared with similar fixed-fulcrum devices.

Accordingly, the object of the present invention is to provide a controllever device, wherein the lever ratio can be easily adjusted and havingsuch characteristics as to overcome the drawbacks cited with referenceto the prior art.

This and other objects are achieved by means of a control lever devicefor a vehicle according to claim 1.

In order to better understand the invention and appreciate theadvantages thereof, an embodiment thereof will be described below by wayof non-limiting example, with reference to the annexed drawings, inwhich:

FIG. 1 is a side view of a lever device according to an embodiment ofthe invention;

FIG. 2 is a sectional view of the lever device shown in FIG. 1;

FIG. 3 is a partial perspective side view of the device in FIG. 1;

FIG. 4 is the same view as in FIG. 3, in which a part of the device hasbeen omitted;

FIG. 5 is a top view of a detail of the device in FIG. 3;

FIG. 6 is a partial exploded view of the device in FIG. 3;

FIG. 7 is a sectional view of a detail of the device in FIG. 1;

FIG. 8 is a sectional view of a detail of the device in FIG. 1 in twoadjustment configurations;

FIG. 9 is an exploded view of a further detail of the device in FIG. 1;

FIG. 10 is an enlarged perspective view of a detail of the device inFIG. 9;

FIG. 11 is a side view of a lever device according to a furtherembodiment of the invention;

FIG. 12 is a sectional view of the lever device in FIG. 11.

With reference to the figures, with 1 has been generally designated alever device for operating a hydraulic actuator 3, such as the brakepump of the braking system or hydraulic clutch of a motorcycle. In theexample referred to herein, the operating lever is the manual controllever associated to a motorcycle handlebar 4 (only partially indicatedwith the dotted line in FIG. 1). By acting thereon, the brake pump 3 ofthe braking system can be operated. Said lever will be referred toherein below as the brake lever 2. The brake lever 2 is known to beplaced at the right end of the motorcycle handlebar, in the vicinity ofthe grip to which the accelerator control is associated.

The lever device 1 comprises a support 5 being provided with means forintegral connection to a bearing structure, which in the example is themotorcycle handlebar 4.

The brake lever 2 comprises a head 2 a from which a tapered part 2 bextends in a main longitudinal direction X-X. The tapered part isintended to be grasped by a user of the motorcycle with the fingers ofhis/her hands, while his/her palm is rested on the corresponding grip onthe handlebar. The tapered part 2 b of the brake lever 2 is shapedaccording to a curved line such as to be ergonomic and facilitate thegrip of the same. In the present description, by “longitudinal directionX-X” is intended to mean that direction defined by the straight linepassing through the head 2 a of the brake lever 2 and interpolating thedevelopment of the tapered part 2 b (FIG. 1).

In the example in the figure, the head 2 a and the tapered part 2 b ofthe brake lever 2 are two distinct parts that are joined to each otherby means of a connection screw or pin. The brake lever 2 can, however,be also provided as one piece.

The head 2 a of the brake lever 2 is pivotally mounted to the support 5by means of a pin 6, such as to be angularly movable close to and awayfrom the corresponding grip on the handlebar 4. The pin 6 extends in adirection Z-Z substantially coincident with the normal to the planepassing through the brake lever 2 and handlebar 4 (i.e. normal to theplane of the drawing in FIG. 1).

The brake pump 3 is integral with the support 5, and in the example, ispositioned such that a piston 7 contained therein is movable in acrosswise direction Y-Y directed from the handlebar 4 to the brake lever2, between an end-of-stroke rest position in which the piston 7 ispushed by a counter-spring 8, and a forward operative position to whichthe piston 7 moves when the brake pump 3 is operated counteracting theaction of the counter-spring 8 and the pressure of the brake fluidcontained in the body of the brake pump 3. Particularly, when shiftingfrom the rest end-of-stroke position to the forward position, the piston7 moves in the crosswise direction Y-Y in the sense of moving close tothe handlebar 4.

A control rod 10 substantially extending in the crosswise direction Y-Yand projecting from the end facing the brake lever 2 of the body of thebrake pump 3 is connected to the piston 7. By acting on the control rod10 with a preset axial force, the operation of the brake Pump 3 isobtained, i.e. the forward movement of the piston 7 from the restend-of-stroke position to a forward position.

In an entirely conventional manner, the brake pump 3 is provided withinlet and outlet ports for hydraulic fluid. The rest end-of-strokeposition of the piston 7 is adjusted such that, in this position, thepiston 7 does not occlude the inlet port for the hydraulic fluid of thebrake pump 3.

From what has been discussed above, derives that the movement of thebrake lever 2 close to or away from the grip on the handlebar 4 alsodefines the simultaneous movement of the brake lever 2 close to or awayfrom the brake pump 3, respectively.

In accordance with an embodiment as illustrated in FIGS. 1 to 10, thelever device 1 also comprises a timing lever 9, which is hinged to thesupport 5 and operatively associated to, preferably pivotally connectedto, the brake lever 2 in order to act on the control rod 10 and operatethe brake pump 3 while the brake lever 2 is moving close to the brakepump.

Preferably, the timing lever 9 is aligned to the brake lever 2 and ispivoted to the support 5 at the pin 6, such as to move together with thebrake lever 2 close to and away from the brake pump 3, and accordinglythe grip on the handlebar 4.

The rear portion of the timing lever 9 has an abutment plane 13, whichis intended to be a stop for the rotation of the timing lever 9 aboutthe pin 6 in the movement away from the brake pump 3 (counter-clockwisewith reference to FIGS. 1 and 2). In fact, when the timing lever 9 isrotated away from the brake pump 3, the abutment plane 13 comes tointerfere with the support 5 and abuts against the latter in anend-of-stroke position.

The action applied by the counter spring 8 on the piston 7 of the brakepump 3 causes the control rod 10 to act on the timing lever 9 in thesense that it holds the latter into abutment against the support 5 witha preset elastic load.

The lever device 1 further comprises an adjustment member 12 connectedto the timing lever 9 or, when this timing lever is not provided (FIG.11, 12), directly to the brake lever 2 and having a seat 22 foraccommodating the end of the control rod 10 such as to transmit theoperating force from the brake lever 2, either directly or indirectly,through the control rod 10 to the piston 7.

According to the invention, the adjustment member 12 is pivoted about anaxis of adjustment and the seat 22 is eccentric relative to this axis ofadjustment such that the position of the seat 22 in the direction of theperpendicular distance between the seat 22 and the direction of movementY-Y, of the piston 7 and the perpendicular distance between the seat 22and the axis of rotation of the brake lever 2 (i.e. the axis defined bythe pin 6) can be adjusted by simply rotating of the adjustment member12. Said variation in the position of the seat 22 causes a variation inthe orientation of the control rod 10 relative to the axis of rotationof the brake lever 2, and thus a variation in the lever ratio.

In accordance with a preferred embodiment, the adjustment member 12comprises a stem 23 which is pivotally accommodated in a through hole 11that is formed in the timing lever 9 (or alternatively directly in thebrake lever 2 when the timing lever is not provided) and a head 12 aprotruding to the hydraulic actuator 3 and defining said eccentric seat22 which accommodates the end of the control rod 10. Thereby, theadjustment member 12 and the control rod 10 are interposed in seriesbetween the brake lever 2 and the hydraulic piston 7.

Preferably, the stem 23 of the adjustment member has two opposite stopseats 24, i.e. arranged at 180° angular pitch, and suitable to beengaged by a stop dowel 25 that is elastically biased against the stem23 by a stop spring 26. As may be seen for example in FIG. 7, the stopspring 26 and the stop dowel 25 are preferably accommodated in asuitable seat, such as a blind hole 27 that is formed in the timinglever 9 transversal to the through hole 11. Thereby, the adjustmentmember 12 can be adjusted in two discrete angular positions, whichprovide two different lever ratios and are adopted and maintained bymeans of snap-engagement between the stop dowel 25 and the correspondingstop seat 24 of the stem 23.

In order to facilitate the angular positioning of the adjustment member12, the end of the stem 23 opposite the head 12 a and facing outwards ofthe lever device 1 is preferably provided with a manual or toolengagement portion, such as a seat 28 to receive the tip of ascrewdriver. The end of the stem 23 forming the tool seat 28 projectsfrom the through hole 11 either within or through an opening 38 formedin the brake lever 2, particularly in the head 2 a that allows access tothe seat 28 from the outside.

In the proximity of the edge of opening 38, a mark is advantageouslyarranged which indicates one or more, preferably two adjustmentpositions (e.g. by means of + and − symbols) which act as a referencefor the angular positioning of the adjustment member 12.

FIG. 8 illustrates how the adjustment of the angular position of theadjustment member and the consequent adjustment of the inclination ofthe control rod 10 (that works as a truss rod being subjected to anaxial compression force) causes a variation in the perpendiculardistance between reaction force of the piston applied to the lever 2 andthe fulcrum thereof (pin 6), whereas the perpendicular distance betweenthe operating manual force acting on the same lever 2 and the fulcrumthereof (pin 6) is unchanged in order to obtain the adjustment of thelever ratio as desired.

In accordance with an advantageous embodiment, the head 12 a of theadjustment member 12 is enlarged relative to the stem 23 thereof, and itis in direct pressing contact with the timing lever 9, or when a timinglever is not provided, with the brake lever 2, such that the adjustmentmember transmits the operating force from the lever to the control rod10 substantially only through the head 12 a and not also through thestem 23 that is advantageously not subject to axial stress.

In accordance with a further embodiment of the invention, the stem 23 ofthe adjustment member 12 is threaded and screwed within a correspondinginner threading of the through hole 11. Thereby, when the adjustmentmember 12 is either tightened or loosened relative to the timing lever9, and thus changing the distance of the head 12 a from the timing lever9, one obtains an adjustment on the control rod 10 which is moved eitherclose to or away from the brake lever 2, and thus the adjustment of saidrest end-of-stroke position of the piston 7 within the brake pump 3. Inorder to allow the snap engagement between the stop dowel 25 and thecorresponding stop seats 24 of the stem 23, despite the furtherlongitudinal adjustment of the adjustment member 12, these stop seats 24are advantageously provided with an elongated shape in the longitudinaldirection of the stem 23.

Preferably, the end of the control rod 10 acting against the adjustmentmember 12 is rounded, whereas the eccentric seat 23 preferably has aflared semicircular shape and is suitable to accommodate said roundedend in the various adjustment positions and preventing a separationbetween the seat and the end of the control rod.

The rotation stop of the timing lever 9 and brake lever 2 in theirmovement close to (clockwise direction with reference to FIGS. 1 and 2)the brake pump 3 is determined by the configuration in which the leveris rested against the handlebar, or when the lever device is dismountedfrom the handlebar, by the maximum forward operating position allowedfor the piston 7 before the latter comes to, abut against the bottom ofthe body of the brake pump 3 or the counter-spring 8 is pack-compressed.

In accordance with a further embodiment, the lever device 1 is alsoprovided with means 15 for adjusting the position of the brake lever 2relative to the timing lever 9, i.e. the adjustment of the distance ofthe tapered part 2 b of the brake lever 2 from the corresponding grip ofthe handlebar 4.

Said means 15 for adjusting the position of the brake lever 2 relativeto the timing lever 9 comprise a timing member, preferably a pin 16,which extends for example substantially in said longitudinal directionX-X. The pin 16 engages the brake lever 2 in an axially adjustablemanner, in said longitudinal direction X-X in the example, and at thesame time, is engaged in abutment against the timing lever 9 such that,a longitudinal displacement of the pin 16 relative to the brake lever 2corresponds to a change in the position of the brake lever 2 relative tothe timing lever 9.

Advantageously, the axially adjustable engagement such as in thelongitudinal direction X-X between the pin 16 and the brake lever 2 isprovided by the pin 16 having an outer thread that is screw-engagedwithin a threaded through-hole 18 which is directly formed in the head 2a of the brake lever 2 or in a centering support 14 that is pivoted onsaid head 2 a such as to be capable of rotating about an axis parallelto the axis of rotation of the lever 2 (pin 6).

Consequently, when the pin 16 is rotated relative to the centeringsupport 14 or relative to the head 2 a of the brake lever 2, therelative position of the pin 16 can be changed relative to the brakelever 2 in the longitudinal direction X-X, and thus the angular distancebetween the brake lever 2 and the timing lever 9.

In order to hold the end 20 of the threaded pin 16 into abutment againstthe timing lever 9, the lever device 1 comprises elastic means 19biasing the head 2 a of the brake lever 2 against the timing lever 9. Inthe illustrative example as shown in the figures, the elastic means 19comprise a pair of helical springs 19, each acting between opposite endportions of the brake lever 2 and timing lever 9, in the sense ofcausing the brake lever 2 to rotate about the pin 6 by moving close tothe brake pump 3 (clockwise with reference to FIG. 1), thus recoveringany clearance therebetween and preventing said levers from impactingagainst each other in the presence of vibrations and the like.

Preferably, the end 20 of the threaded pin 16 is circumferentiallyundulated or knurled and is engaged into abutment within a correspondingcircumferentially undulated or knurled recess 21 being formed in thetiming lever 9. Due to said knurling or undulation, the adjustmentconfiguration of the adjustment pin 16 is maintained even in thepresence of vibrations and impacts against the lever device 1.

Preferably, the pin 16 extends in the longitudinal direction X-X as asubstantial extension of the brake lever 2 and more precisely of thetapered part 2 b of the latter.

FIGS. 9 and 10 illustrate an advantageous embodiment of the connectionbetween the tapered part 2 b and the head 2 a of the brake lever 2,which are preferably hinged to each other in a pivotal or, in otherwords, “collapsible” manner, about a collapse axis C-C transversal tothe longitudinal axis X-X of the brake lever 2, by means of a retainingspring 29 being interposed therebetween. The retaining spring 29comprises a generally plane and annular portion 30 being sandwichedbetween two opposite sliding surfaces 35, 35′ of a hinge portion 31 ofthe lever head 2 a and an adjacent hinge portion 32 of the tapered part2 b of the lever 2 and fitted on a pin (not shown in the figures) whichprovides the collapse axis C-C. A stop tongue 33 protrudes transversallyfrom the annular portion 30, which engages a suitable seat 34 beingformed in a first one of the hinge portions 31, 32 in order to preventthe retaining spring 29 from rotating about the collapse axis C-C. Theannular portion 30 comprises a projection, such as an indentation 37which engages a corresponding seat, such as a notch 36 being formed inthe sliding surface 35′ of the second one of said hinge portions 31, 32.Preferably, the stop tongue 33 engages a seat 34 that is formed in thehinge portion 31 of the lever head 2 a and the indentation 37 engages anotch 36 being formed in the hinge portion 32 of the tapered part 2 b ofthe lever 2. Thereby the elastic engagement between the indentation 34and the notch 36 provides a mutual elastic snap-positioning between thetwo portions of the brake lever 2 and also defines the threshold valuefor the side impact force which causes the lateral collapse of lever 2.

FIGS. 11 and 12 show a further embodiment of the invention, in which thelever device is not provided with a timing lever and the adjustmentmember 12 is directly arranged between the main lever 2 and the controlrod 10 for the hydraulic piston 7 and suitable to adjust the orientationof the control rod 10 relative to the piston 7 and fulcrum (pin 6) ofthe brake lever 2, as well as (as a function of the optional furtherfunction of longitudinal adjustment) the relative position between thebrake lever 2 and the piston 7.

The shape and function of the individual parts described above withrelation to the first embodiment (FIGS. 1-10) and compatible with thesecond embodiment (FIG. 11, 12) are preferably substantially unchanged.

The lever device according to the invention has a number of advantages.Particularly, it allows the lever ratio of the device to be easilyadjusted by means of a particularly simple and solid mechanism that hasreduced overall dimensions as compared with prior art solutions.

1. A lever device for operating a hydraulic actuator for a motorcycle,comprising: a support to be connected to a bearing structure, ahydraulic actuator connected to the support; a main lever pivotallyconnected to the support and movable toward or away from said hydraulicactuator, a control rod and an adjustment member that are interposed inseries between the main lever and a piston of said hydraulic actuatorsuch as to transmit an actuating movement by the lever to said piston,wherein said adjustment member is pivotally supported about an axis ofadjustment and defines a seat that accommodates an end of the controlrod, wherein said seat is eccentric relative to said axis of adjustment,such that a rotation of the adjustment member causes the adjustment ofthe orientation of the control rod relative to the axis of rotation ofthe lever, and thus the adjustment of the lever ratio.
 2. The leverdevice according to claim 1, comprising a timing lever that is pivotallyconnected to said support and connected to the main lever, wherein saidadjustment member is supported by said timing lever such as to transmitthe actuating movement of the lever by means of said timing lever, saidadjustment member and said control rod to said piston.
 3. The leverdevice according to claim 1, wherein said adjustment member is arrangedsuch that the rotation of the adjustment member about the axis ofadjustment causes an adjustment of the distance of the eccentric seatboth from the fulcrum of the lever and from the direction of movement(Y-Y) of the piston.
 4. The lever device according to claim 1, whereinthe adjustment member comprises a stem that is pivotally accommodatedwithin a hole formed in the lever or in a timing lever and a headprotruding to the hydraulic actuator and defining said eccentric seat.5. The lever device according to claim 4, comprising means suitable tostop said adjustment member in a plurality of discrete adjustmentpositions.
 6. The lever device according to claim 4, wherein said stemcomprises two opposite stop seats that are suitable to be engaged by astop dowel that is elastically biased against the stem by a stop spring.7. The lever device according to claim 1, wherein an end of theadjustment member opposite the eccentric seat and substantially facingoutwards of the lever device forms a manual engagement portion or a seatto receive a tool for allowing the manual adjustment of the lever ratio.8. The lever device according to claim 1, wherein the adjustment memberis threaded and screwed within a corresponding inner threading of ahole, such that it also allows, in addition to the adjustment of thelever ratio, an adjustment of the distance of the eccentric seat fromthe lever or from a timing lever, and thus an adjustment of the restend-of-stroke position of the piston.
 9. The lever device according toclaim 6, wherein the stop seats of the adjustment member have anelongated shape in the longitudinal direction of the stem thereof. 10.The lever device according to claim 1, wherein said eccentric seat has aflared semicircular shape and is suitable to accommodate the end, alsosemicircular-shaped, of the control rod in the possible adjustmentpositions in an secure manner.
 11. The lever device according to claim1, wherein said adjustment member comprises a stem and a widened headrelative to the stem and being in pressing contact with said lever ortiming lever such that the adjustment member transmits the actuatingforce from the lever to the control rod substantially only via saidhead.
 12. The lever device according to claim 1, comprising a markindicating one or more reference positions for the angular position ofthe adjustment member.